The chances of cracking open a double yolked egg are pretty slim. One tenth of one per cent in fact. [via dailymail]

So imagine the odds of going through a half-dozen box from the supermarket and finding that all of them had two yolks.

Fiona Exon has done exactly that. The art gallery owner was preparing scrambled eggs for Sunday breakfast when she started cracking the eggs.

As each one turned out to be double-yolked, she went from being pleasantly surprised to shocked.

Understandably - because the odds of a whole box of six being so is supposedly one in a trillion.

Miss Exon, who lives in the Eden Valley in Cumbria, said: 'We bought a half dozen eggs from Morrisons and when I started to crack them to make scrambled eggs I was astounded when the first was a double-yolker.

I had only ever seen one double yolk egg before, and that was when I was young. Cracking the second, I gasped when it too was a double.

'When the third was the same I called my partner Hector through to the kitchen and when the fourth was a double, then the fifth we began to feel a little spooked.

'By the sixth double we were just gobsmacked. I had to get my camera and take a picture.'

British Egg Information Service spokesman Kevin Coles said: 'The chances of an egg coming out with a double yolk are 0.1 per cent. It's extremely unusual to find six such eggs together in the one box.'

Mr Coles said double eggs were common among younger hens and added: 'When hens start laying eggs they often produce double eggs.'

Mr Coles said double yolk eggs were larger, so that may explain why they would be grouped together by automatic sorting machines.

Studies in America have used selective breeding to increase the chances of double yolks, but the idea did not take off commercially because of the inability to guarantee a double yolk in every egg meant it was impossible to market the concept.